1. The Erken Laboratory Thorsten Blenckner

3. Lake Erken Lake Erken, dimictic Catchment area (km 2 )141 Lake area (km 2 )24 Mean depth (m)9 Max depth (m)21 Residence time (ys)7 Mean TP (µg/l)27 Mean summer Chl a (µg/l)4

4. Monitoring programme Manual monitoring (winter monthly, otherwise weekly, 1974-79, 1993-now): –Temp., Oxygen, Secchi, pH, alk, cond, colour, diss. + part.+total nutrients, Chl a, phytoplankton counts

5. Monitoring programme Automatic monitoring (Island, hourly, 1988-now): –Weather station: air temperature, global radiation, PAR, wind speed and direction, –Water temperature 1, 2.5 and 14 m –Delayed fluorescence Automatic monitoring (Float, 30 min, 1988-now): –Water temperature every 0.5 m YSI 6920 Sonde (last year): Temp., Cond., DO, Fluor., pH

6. Monitoring programme Automatic monitoring (Erken inflow and Galten inflow, hourly): –Discharge, water temperature, CDOM (fluorometer) and turbidity (trans- missometer, 660nm)

7. Data http://erken.dyndns.org/LoggerWebpage/ AutomaticStations.htm